package com.LeeCode;

/**
 * 第N个泰波纳契数
 */

public class Code1137 {
    public static void main(String[] args) {

    }

    public int tribonacci(int n) {
        if (n == 0) return 0;
        if (n == 1) return 1;
        if (n == 2) return 1;

        int a = 0, b = 1, c = 1, ans = 0;
        for (int i = 3; i <= n; i++) {
            ans = a + b + c;
            a = b;
            b = c;
            c = ans;
        }
        return ans;
    }
}
